Is there gender bias in awarding cum laude for the PhD thesis?

In the Dutch academic system, PhD theses can be awarded with cum laude and at most 5% of all PhD graduates receive this selective distinction for their thesis. In this paper, we investigate whether there is gender bias in awarding cum laude, using data from one of the major Dutch research universities. We measure the quality of the PhD theses using bibliometric data. A main result is that the set of PhD theses receiving cum laude on average do not have a higher quality than the best theses not getting cum laude. A second main result is that, after controlling for the quality of the PhD theses, women still have a substantially lower probability to receive cum laude. These results strongly suggest that the distribution of awards suffers from gender bias, and the study creates a strong doubt about the adequacy of the procedures leading to cum laude for the PhD thesis.